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By OlWeldinrig - 8 Years Ago
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Thought I better share,a little bit of horse trading and I ended up with this early 60's build 312 this weekend. std bore 312 Ported and polished "G" heads deep sump pan
Everything looks very unused,very tight timeing chain,clean bottom end other than mouse house causeing some discolouration on throws.Also mystery cam that's I have not pulled yet.
Finally feel like I have something of interest to share to group.
Dave
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By OlWeldinrig - 8 Years Ago
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By the way that's 40 yr old grease in cylinders,very little surface rust.
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By Oldmics - 8 Years Ago
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So whats the plan for this goodie?
Oldmics
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By OlWeldinrig - 8 Years Ago
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Plan is to strip and clean it for now.I hopeing I can re-use most everything,although I was told it would only run on AV gas so that has me a bit worried.I have to pull it apart first and see what I have.I have been trying to purchace a real nice 57 tudor that would be a nice home for this.Or maybe my weldin truck...
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By OlWeldinrig - 8 Years Ago
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By the way its a Canadian 57 block "VV" 1058...
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By PF Arcand - 8 Years Ago
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Looks like hi comp pistons alright. Before you spend money on the block, clean it up well & check for cracks, especially in the mains area. Over tightening the main bolts on 312s led to disasters sometimes.. Good luck.
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By OlWeldinrig - 8 Years Ago
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Nothing visual yet for cracks,pulled all but rear one.I`ll post another pic but everything is washing up fine except for the rust in the valley.No ridge and hone marks right to top.Measures 3.875(324 cubes).Rod throws all look nice so far but some staining on mains.
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By OlWeldinrig - 8 Years Ago
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Moon Eliminator FT•4
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By OlWeldinrig - 8 Years Ago
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Better pic
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By Oldmics - 8 Years Ago
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I had never heard of "Moon" Cams so I did some diggin and found this information from a website called "The H.A.M.B.
Some real history here about Moon Cams
"Dean Moon partnered up with Chuck Potvin to mfr front drive blower systems, and Chuck brought along his cam grinding operation. After Chuck (and Dean) died, Chico carried on the 'Moon Cams' service..."
In case you dont know "Dean Moon" is the Moon Eyes guy. He is responsable for quite a few aluminun intakes that Merc and Ford used and much more!
Potvin Cams reputation speaks for itself.
I would venture a guess that the 36 - 68 is the timing event.
Oldmics
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By Ted - 8 Years Ago
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Assuming the 36-68 number on the camshaft is the timing event, then that would make that a 284° duration camshaft. A micrometer check of the lobes would give a lobe lift value which could be converted to a valve lift value by multiplying by the rocker arm ratio.
Those pop up pistons will work with the ‘471’ casting heads and be pump gas compatible. The '471' heads are still big valved but have combustion chambers in the 82cc range. On the other hand, those pistons can likely have the tops machined off and be used with your existing ‘G’ heads and also be pump gas compatible. This would require a rebalance of the rotating assembly though. You would need to cc the heads to confirm their combustion chamber sizes so that an accurate compression ratio determination can be made. 69cc was the nominal value for the ‘G’ heads but they can be larger than this before any milling has been performed. Based on the code date on the pictured head, it’s an unposted head which means checking the measuring pads on the exhaust sides of the heads and see how much they have been milled. Unmilled heads will be 1.000” at the pads give or take a few thousandts. The factory did not recommend milling beyond 0.010” on the unposted heads but supplemental posts can be added to the heads to improve head gasket sealing when the compression ratio is raised.
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By OlWeldinrig - 8 Years Ago
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Ted,Thanks for chimeing in.I was hopeing maybe the 113s would work or like you said maybe trim the domes.I have a set of 113s.Although it would be nice to use the ported heads that it came with.On the heads measured I am reading 1.001 on the pad.I have checked most of my heads I have laying around and most measure in 1.007 range or slightly less.I am not sure if this is because they are Canadian pieces?Or is that a common stock height.
How does a guy go about figuring out the cc of domes?Upside down in a beaker and try to measure liquid displaced?It would be nice to figure out dome size.I see the Mummert pistons are 10cc domes,I don't know if I'd want to shave whole dome off but if I could get them to a similar size maybe.
Roughly how much comp is lost with composite head gaskets?This engine had steel gaskets in it.There is a 7 liter Galaxie running doubled gaskets in it to reduce some compression.Are there thicker gaskets available for Ys?I warped a head on a 5.9 cummins once and that was what we did to return to spec after heads were planed(.050 gasket).I don't like the double gasket idea but is there a similar option?
I'd like to try and use everything that came with engine to maybe preserve it as it was,and possibly keep rebuild cost minimal if possible.
Thanks Dave
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By OlWeldinrig - 8 Years Ago
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OldMics
You had better luck than me,I could hardly find anything other than Potvin ground they're cams.Checked the barn,Hamb,here too.Searched everyplace I could think of.
I did come to conclusion it was built a long time ago!
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By OlWeldinrig - 8 Years Ago
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 I was in town today so I took the girl in with me,didn't know that a cam profile machine existed...
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By OlWeldinrig - 8 Years Ago
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Ted,can chambers on the G heads be relieved enough drop a bit of compression and increase the flow.It has stock size valves still installed.I was wondering if opening up chamber by unshrouding for say 2.02,1.60 combo and some relieving of flat side around exhaust valve,perimeter of intake seat faceing outwards and possibly around spark plug side all the way across.Could I shave enough cc`s to make a substantial difference and improve flow of chamber?The piston domes need to be measured due to the fact they have a hollow spot under dome and cannot be cut clean off.
Thanks Dave
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By Oldmics - 8 Years Ago
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While I am sure that report was done in good faith - there are some things that I would question.
Did you actually watch the test proceedure being done? Which lobes did he actually take measurements from?
Oldmics
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By OlWeldinrig - 8 Years Ago
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He was pretty busy did it in a little bit of a hurry.But for free,it is very close I would think but not exact.Close enough to figure out its mostly ridicullously huge.And he charged nothing to look quick.
Dave
Oldmics (4/6/2016)
While I am sure that report was done in good faith - there are some things that I would question. Did you actually watch the test proceedure being done? Which lobes did he actually take measurements from? Oldmics
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By OlWeldinrig - 8 Years Ago
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The front two lobes were cleaned,I hadn't planned on goin into town so it wasn't spotless as I would have liked.It would be real close,he saved the info for future.
OlWeldinrig (4/6/2016)
He was pretty busy did it in a little bit of a hurry.But for free,it is very close I would think but not exact.Close enough to figure out its mostly ridicullously huge.And he charged nothing to look quick. Dave Oldmics (4/6/2016)
While I am sure that report was done in good faith - there are some things that I would question. Did you actually watch the test proceedure being done? Which lobes did he actually take measurements from? Oldmics
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By charliemccraney - 8 Years Ago
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Exact specs aren't that important. If that's in the ballpark, then It's too big for street use. That engine probably won't even start to run until 2500-3000rpm.
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By OlWeldinrig - 8 Years Ago
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Well the old saying is...one in hand is better than 4 in the bush.Funds are not high right now,so we'll see.Likely put it in for now.Don't have the money to buy another one.
charliemccraney (4/6/2016)
Exact specs aren't that important. If that's in the ballpark, then It's too big for street use. That engine probably won't even start to run until 2500-3000rpm.
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By charliemccraney - 8 Years Ago
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Maybe you can sell it or work out a trade.
It will be beyond too big for your truck if you plan to use it as a truck.
You can probably make it move your car or truck, but it won't be fun at all for street use. Even if you could tolerate the idle and the lower rpm mannerisms, the rest of the car will not be up to the task. If you don't have money for a cam, then you don't have the near the money to make that work.
It is a bad call if you use that in a street vehicle.
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By Oldmics - 8 Years Ago
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QUOTE
"The front two lobes were cleaned,I hadn't planned on goin into town so it wasn't spotless as I would have liked"
________________________________________________________________________________________________________
If the first two lobes were used for the measurements - then what was measured was exhaust #5 and exhaust #1.
Cant get the correct event values from that measurment position.
If that actual lift is correct (I would get out the calipers) that is a HUGE bumpstick !
Oldmics
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By Small block - 8 Years Ago
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Oldmics (4/6/2016)
QUOTE
"The front two lobes were cleaned,I hadn't planned on goin into town so it wasn't spotless as I would have liked"
________________________________________________________________________________________________________
If the first two lobes were used for the measurements - then what was measured was exhaust #5 and exhaust #1.
Cant get the correct event values from that measurment position.
If that actual lift is correct (I would get out the calipers) that is a HUGE bumpstick !
Oldmics
Have it reground there are plenty of shops that will re do it to your specs, About Dean Moon He was the Guy that Shelby teamed up with to do the race engines for his Cobras!
The first cobra was built in Deans shop!
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By Ted - 8 Years Ago
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I agree with John in that if only the front two lobes on the camshaft were cleaned, then it sounds like only two exhaust lobes were checked. If you do stick that camshaft back in the engine, then you can reverse engineer the actual specs yourself with a dial indicator and degree wheel. If you send me the camshaft and simply pay the shipping both ways, I’ll check the camshaft for you. I’m curious to the specs on that camshaft myself.
Grinding on the combustion chambers for the amount needed to reduce the compression ratio a significant amount is not recommended. The heads are already prone to cracking in certain areas and grinding on the combustion chambers could just bring that to the forefront especially if your heads are the ‘unposted’ variety.
Composition head gaskets in lieu of steel shim head gaskets will reduce the compression ratio approximately 0.7:1 which helps a bunch. Some rough math on a +060 312 with 10cc domes and 69 cc heads has the static compression ratio at 11.27:1. The dynamic compression ratio with a 284° duration camshaft would be in the neighborhood of 9.24:1. Adding the composition gaskets has the SCR at 10.56:1 and the DCR at 8.67:1. That DCR value is still too high for premium pump gas and needs to be 8:1 or less to be safe. Assuming the domes are 10cc, then removing 7 cc of dome would have the SCR at 9.68:1 and the DCR at 7.96:1 which would be streetable. The simplest way to remove a known amount of dome volume is to do it by weight. Each 2.7 grams removed from the piston tops would be 1 cc.
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By OlWeldinrig - 8 Years Ago
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Ted,I am sure he did the right lobes,I meant front ex/in.He said it was a single pattern cam and to tell you the truth I didn't see exactly what lobes he did his assembly room was jammed right full of engines in assembly stages and I didn't want to wander all the in being half dirty.I do fully trust him,best around here and many from out of province use him as well.
I probably could send you the cam for further diagnosis.There is a couple very tiny pits on closing side of very back lobe that maybe I should think about and a second opinion would be apreciated.
On the head chamber work,I was thinking mainly about some radius work across the square side opposite spark plug and the couple "bumps" either side of spark plug where the c1,c2 etc don't have them,I am betting they are solid cast in behind this.A guy could grind that area straight across possibly(spark plug side).Even polishing chamber will drop a little. I have a badly pitted G head I can grind and play with and cc to see what I can get away with.Possibly drill holes to see how much metal I have in these areas.When a 2.02 valve is used some unshrouding is needed correct?This is why I was thinking about possible chamber work.There is bound to be improvements from this.Or I could be totally wrong,thats why I am asking....
Thanks Dave
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By OlWeldinrig - 8 Years Ago
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I understand what you are saying Charlie,Way to big for what I am needing.I feel like I have to at least try run this cam.I have almost next to nothing invested in this and it literally fell into my lap.I have a couple fairly light projects it may work ok in.Probably the smartest thing to do is order some flat tops and a smaller cam but I better give this a try first...Just because.
Dave
charliemccraney (4/6/2016)
Maybe you can sell it or work out a trade. It will be beyond too big for your truck if you plan to use it as a truck. You can probably make it move your car or truck, but it won't be fun at all for street use. Even if you could tolerate the idle and the lower rpm mannerisms, the rest of the car will not be up to the task. If you don't have money for a cam, then you don't have the near the money to make that work. It is a bad call if you use that in a street vehicle.
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By OlWeldinrig - 8 Years Ago
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PF Arcand (4/5/2016)
Looks like hi comp pistons alright. Before you spend money on the block, clean it up well & check for cracks, especially in the mains area. Over tightening the main bolts on 312s led to disasters sometimes.. Good luck.
It is a Canadian block,a heavier breed,visually everything is fine but might check it out.Also rear main bolt holes are same depth and threaded to bottom.I believe that's a Canadian block only aspect.
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